Stormy Weather

When the sun's fury maxes out, Earth may take a hit

Part one in a two-part series on the Earth-sun connection.

False-color ultraviolet image shows brightening of Earth’s auroral oval last July 15, minutes after a magnetic storm struck our planet. The storm had erupted on the sun the previous day. The ultraviolet emissions, recorded by the IMAGE satellite, stem from energetic electrons bombarding molecular nitrogen in Earth’s atmosphere. Stephen Mende, Harald Frey/UC Berkeley
Close-ups of a flare that erupted on the sun July 14th. Left: The relatively cool, dense loops of electrically charged gas in this magnetically active region of the sun’s corona are held down by a lid of hotter, more tenuous loops that aren’t visible in this picture.